Machine punch having an ejector pin



Dec. 14, 1965 c. E. LARsoN MACHINE PUNCH HAVING AN EJECTOR PIN O 2 6 9 6 8 m m 4 IZIII..

\\" nie Filed May 6, 1965 FIGA INVENTOR. FG., 6 CARL ERNEST LARsoN 7 plu F.

United States Patent O 3,222,968 MACHINE PUNCH HAVING AN EJECTOR PIN Carl Ernest Larson, Bemus Point, N.Y., assignor to The Producto Machine Company, Bridgeport, Conn., a corporation of Connecticut Filed May 6, 1963, Ser. No. 278,262 11 Claims. (Cl. 83-128) This invention relates to punches used to pierce openings of various shapes and sizes in sheet material, and particularly to such punches having slug ejecting means associated therewith.

In the past, Various means have been employed to eject slugs from punched material. Ejectors are essential to punching operations to assure the slug being driven beyond the pierced material into the relief or exit opening in the die. Without some positive means of ejection, it is possible for a slug to at least momentarily adhere to the piercing end of the punch, in which case the slug will be lifted from the die hole and deposited either under the stock or on top of it, depending on where the slug pulls free of the punch. In either case, damage to the punch, and/or die, and/or material can result in a successive operation. Effort is always made to keep the punch end and the material to be punched absolutely clean, but it often occurs that lubricant or foreign matter accumulates in a sufficient amount to create the condition wherein an ejector is needed.

Considering then that efficient punching operations require the use of ejectors, a problem arises as to how to handle the required periodic grinding or sharpening of the punch ends. In all cases wherein ejection of a slug is positive, springs or internally mounted pins so utilized must be displaced from the piercing ends. Many punch operations require multiple punches and often in close arrangement, thus the need to be able to quickly and easily displace these members is of prime importance. This, of course, takes into consideration the fact that many present machine items must be produced in large quantities at an economical cost. Thus, it may be assumed that repeated grinding of the punch piercing ends must take place many times during the manufacture of thousands of any given items.

Prior known punches with ejector means employ external means to hold the ejector means retracted from the punch face during a grinding operation on the punch piercing face. Such external means precludes the close spacing of punches since the external retracting means interferes with adjacent closely spaced punches. Certain other types of ejector means are releasably held within the punch and can be withdrawn or inserted into a chuck means within the punch from the piercing end of the punch.

The principal object of the present invention is to provide a punch having an ejector pin means permanently held within the punch structure and capable of being held in a retracted position flush with the piercing end of the punch without utilizing external means to hold it in retracted position.

Another object of the invention is to provide such a punch and ejector pin means in which the forward end of the pin means is spring urged outwardly beyond the piercing end of the punch.

Still another object of the invention is to provide such a punch and ejector pin means in which the forcing of the ejector pin means into the punch beyond the piercing end causes it to be held in retracted position.

Another object of the invention is to provide such a punch and ejector pin means in which the retracted ejector pin means can be released from its retracted position by forcing it further into the punch.

A still further object of the invention is to provide such a punch and ejector pin means that is locked in, and released from retracted position by alternately forcing the ejector pin means into said punch.

In one aspect of the invention, one or a plurality of punches, the latter being located as closely to each other as desired, may be of cylindrical form having flanged heads and may be located within cylindrical passages within a reciprocable head of a punching machine. Each punch may include a necked portion adapted to pass through a cylindrical passage within a bushing mounted in a die block beneath the reciprocating head, and over which die block sheet material is adapted to be fed as slugs in the shape of the piercing end of each punch are punched therefrom.

In another aspect of the invention, each punch may have a reciprocable ejector pin means mounted internally thereof and normally spring urged such that its forward end projects outwardly beyond the piercing end of the punch.

In still another aspect of the invention, a plunger within the punch has a head at its inner end provided with inclined cam notches spaced about its top surface against which one end of a separate member is resiliently urged. The separate member includes ribs spaced about its periphery, and each rib includes at its outer extremity an inclined cam surface corresponding to, and adapted to cooperate with, the inclined cam surfaces of said cam notches on the head of the plunger.

In still another aspect of the invention, both the plunger head and separate member may be mounted for reciprocation within a liner in a counterbore of the punch. The inside peripheral surface of the liner may include spaced, longitudinally extending ribs, the inner extremities of said ribs being provided with inclined cam surfaces adapted to cooperate with the inclined cam surfaces on the oiiter extremities of the ribs on the separate member.

In still another aspect of the invention, there may be provided longitudinally extending grooves alternating with the ribs on the inner periphery of the liner, alternating grooves being blocked off at their inner ends.

The construction and arrangement of the parts are such that inward movement of the plunger causes the head thereof to engage the forward end of the ribs on th separate member, forcing it inwardly against the action of spring means until said ends are inwardly beyond the inclined cam ends of the ribs on the interior surface of the liner, whereupon the spring forces the cooperating cam surfaces on the ribs of the separate member along the corresponding cam surface on the liner ribs, thereby indexing the separate member in a rotary manner. Since alternate longitudinal grooves on the liner are blocked off, alternate inner movement-s of the plunger cause it to be retained within the punch in retracted position, and alternate inner movements of the plunger permit the ribs on the separate member to be received within the unblocked grooves of the liner; thus the spring forces the plunger outwardly.

The punch assembly normally operates with the plunger in its unretracted position so that the ejector pin is resiliently urged outwardly beyond the piercing end of the punch. However, when it is desired to sharpen the piercing end of the punch or punches, the head containing them is removed from the machine, inverted and mounted on the table of a grinding machine, after which each ejector pin is forced inwardly within its punch until its corresponding separate member is indexed such that its ribs are aligned with a blocked off groove in the liner where the ejector pin is retained in retracted position with its forward end flush with the piercing end of the punch. The piercing end of the punch as well as the outer end of 3 the ejector pin are simultaneously ground until the piercing end is sharpened. Thus, the relationship between the piercing end of the punch and the outer end of the ejector pin, when the latter is in its unretracted position, remains the same during subsequent sharpening operations of the punch.

The above, other objects and novel features of the improved punch and ejector pin means will become apparent from the following specification and accompanymg drawing which is merely exemplary.

In the-drawing:

FIG. l is asectonal elevational View of a head supporting a plurality of punches;

FIG. 2 is a sectional elevational view of a die block that cooperates with the head of FIG. l;

FIG. l3 `is a sectional view through a punch to which the principles of the invention have been applied;

FIG. 4 is a fragmentary developed view of certain of the parts shown in FIG. 3;

FIG. 5 is a sectional View taken Vsubstantially along line `55 of FIG. 4, and showing the fragmentary portion in full and in undeveloped condition;

FIG. vv6 is a sectional View 'taken rsubstantially along line 6-6 of FIG. 4, similar to FIG. 5; and

FIG. 7 is a view similar to FIG. 3 but showing the punch in inverted position with certain of the parts positioned differently from thosein FIG. 3.

Referring to the drawing, and particularly to FIGS. 1 and 2, the principles of the invention are shown as applied to a head 16 of a punching machine that reciprocates the head 110 toward and from a die block 11 as is well known. The head V10 may comprise two members -12 and 13 that are held together by screws 14 and -accurately located relative yto each other by pins 15. Member `13 may include bores '16 and counterbores 17 for receivingpunches 18. The Aspacing of adjacent bores and 'counterbores may be any desired amount, and as shown, two are disclosed in relatively' closely spaced relation.

The punches may include cylindrical bodies 19 adapted accurately to lit the bores 1.6. They may also Ahave 'a flanged head 20 adapted to t lcounterbores 17. With the punches 18 within the bores of member 13 and withmember 12 rigidly xed thereto, the punches 18 fare rigidly xedto the head Y10. l

Die block 11 may also comprise two parts 21 and 22 pinned and held together by pins "23 and screws 24. Part 21 'may include bores 25 and counterbores 26 vadapted to receive hardened bushings 27 having 'a bore 28 adapted to receive a reduced section 29 of the punches 18. The member -22 may include a through passage '30 concentric with bore 28 for passingslugs punched yfrom sheet material that is'fed over the top of bushings`27 and beneath punches 18, all as is well known in the art.

.Referringto F-IGS. 3 to 6, inclusive, and particularly to'FIG. 3, each punch 1'8 may include a bore 31, a rst counterbore 32 and a second counterbore 33. An ejector pin 34 having a head 35 may have its shank slidingly tting bore 31, with its head 35 slidinglyitting counterbore 32. Outward movement of pin 34 is stopped by head 35 seating against the shoulder between bore 31 and counterbore 32.

'A lner36 may beheld within the counterbore 33 and it may include a reduced diameter portion 37 extending into counterbore 32. Longitudinally extending, spaced ribs 38 (see alsoFIG. 4) 4are formed along the'inner peripheral surface of the liner 36 from the beginning -of the reduced portion upwardly for a distance substantially greater than'the distance X (FIG. 3) that pin 34 Tprotrud'es from the piercing end 39 of punch 18. The upper end of each rib 38 includes an inclined cam "surface 40, and the space between adjacent ribs 38 forms a groove 41, alternateI ones `of which are blocked off by 'an extension 42 of the cam surface 40, all for a'purpose to be described hereafter.

A member 43 may be mounted within the liner 36. It may include longitudinally extending ribs 44 spaced about its periphery. The lower end of each rib 44 includes an inclined cam surface 45 that has the same inclination as, and is adapted to slide along, the cam surface 40 on ribs 38. A spring 46 mounted withinliner 36 acts on the top of member 43 and on a set screw 47 threaded into the top of counterbore-33.

A plunger 48 is slidingly mounted within the reduced diameter portion 37 of liner 36 and it includes a head 49 having inclined cam notches 50 thereon. The inclination of cam notches 50 is the same as that of cam surfaces 40.

Movement of 34 upwardly (FIG. 3) a sufficient distance forces 48 and -49 upwardly also. Surfaces 50 on head 49 raise rib 44 in slots 41 until surfaces 45 on rib 44 are above the high point of cam surface 40, where-V upon the spring action ofv46 causes surface 45 to slide rightwardly (FIG. 4) on'surfaces 48, and blocking portions 42 prevent rib 44 from passing downwardly and hence prevents plunger 48 Yfrom moving downwardly (FIGS. `3 and 4). It should be noted that blockingV portions 42 occur alternately with slots 41, so that every alternate movement of ejecting pin'34 upward a sucient amount to index it will keep the member 48 up, and every other such alternate movement of pin 34 will 'permit rib 44 to pass down a slot 41.

In other words, the second indexing operation is effected only by forcing ejecting pin 34 upwardly (FIG. 3) sufliciently so that surfaces 50 again contact 45, raising it above the high point of surfaces 40 so that as the spring 46 forces member 43 down, it turns and surfaces 45 slide down cam surface 40, and rib 44'is received by slots 41.

With the head 10 in the 'position shown in FIG. l, the components of the punch 18 are in the positions shown in FIG. 3. Since the length of the ribs 38 substantially exceeds the distance X'that the ejecting pin 34 protrudes from the piercing end'3'9 of punch '18, it will always act to Veject slugs vfrom the material being punched so long as spring 46 is Vheavy enough. However, when it is desired to `sharpen the piercing end v39 of punches `18, head 10 -is removed from the punching machine, inverted and placed onlthe table of a grinding machine with the grinding wheel above the piercing'ends A39 of Athe punches 1S. Punches 18 are,`therefore, in the condition shown in FIG. 7, exceptthat the pins 34 are in extended position vas shown in dotted lines. Pins/'34 are in this extended position 'because the ribs 44 'are inline with open grooves `41 so that spring4'6 forces plunger -48 ldownwardly (FIG. 3), upwardly (FIG. 7). Referring to FIGS. 3 and 4, movement of pin 34 upwardly into bore 31 causes plunger 48 and'head 49 to move upwardly, raising member A43 against the action of spring 46 until the cam surfaces 45 are ,above the highest point of cam surfaces 40, -at which point cam surfaces V50 act as extensions of cam surfaces 40 sothat the action of spring 46 rotates the member 43 as the surfacesA 45 on ribs 44 slide downwardly/along cam surfaces40. However, the next adjacent groove '41 is .blocked by extension 42, thereby preventing the ribs 44 from slidngto the bottom of grooves '41, and hence preventing -spring y"46 from forcing ejecting .pin 48 outwardly Ibeyond the vpiercing end 39 of punch 18. The distance from the bottom of grooves 41 to the extension 42 is such thatwhen the ribs 44 aresupported by extension 42, the outer end ofpin 34 is ush with the4 piercing end 39 .of the` punch. With'thepunch`18in inverted position (FIG. 7), as is the case when the head 10 is fon-the grinding table, ejecting pin .34 remains flush ywith the piercing end 39 ofthe punch 18. lAccordingly, the piercing end 39 and the outerend of pin 34 Ycan beiground Iuntil the former'is sharpened, after which forcing .pin v34 downwardly into bore 31 causes another indexing of member 43,and this lines up a groove l41 thathas no blocking portion 42 with the ribs -44 and thus the spring 46 forces plunger 48.together withejector pin 34 into the position shown in FIG. 3. It is apparent that the punch can be sharpened and resharpened a great number of times, i.e., until the portion B (FIG. 7) is consumed, while the distance X between the piercing end 39 of the punch and the outer end of the pin 34 remains constant.

Although the various features of the improved punch and ejector pin assembly have been shown and described in detail to fully disclose one embodiment of the invention, it will be evident that changes may be made in such details and certain features may be used without others without departing from the principles of the invention.

What is claimed is:

1. In a punch, a body portion having a piercing end; a bore and counterbore within said body portion forming a shoulder therebetween; an ejector pin slidingly received within said bore and having a headed portion slidingly received within said counterbore, said pin extending outwardly beyond said piercing end when said headed p0rtion contacts said shoulder; plunger means mounted within said body portion adapted to contact said headed portion; spring means normally urging said plunger toward said headed portion; and means wholly within said body, located between said plunger and spring means and responsive to the forcing of said ejector pin into said bore such that its outer end is within said bore for selectively restricting the motion of said plunger toward said headed portion, whereby when said punch is inverted, the outer extremity of said ejector pin lies substantially flush with the piercing end of said punch.

2. In a punch, a body portion having a piercing end; a bore and counterbore within said body portion forming a shoulder therebetween; an ejector pin slidingly received within said bore and having a headed portion slidingly received within said counterbore, said pin extending outwardly beyond said piercing end when said headed portion contacts said shoulder; plunger means mounted within said body portion adapted to contact said headed portion; spring means normally urging said plunger toward said headed portion; and means wholly within said body, located between said plunger and spring means and responsive to the action when said ejector pin is forced inwardly beyond said piercing end, to restrict the motion of said plunger toward said headed portion, whereby when said punch is inverted, the outer extremity of said ejector pin lies substantially ush with the piercing end of said punch.

3. In a punch, a body portion having a piercing end; a bore and counterbore within said body portion forming a shoulder therebetween; an ejector pin slidingly received within said bore and having a headed portion slidingly received within said counterbore, said pin extending outwardly beyond said piercing end when said headed portion contacts said shoulder; plunger means mounted within said body portion adapted to contact said headed portion; spring means normally urging said plunger toward said headed portion; and means wholly within said body, located between said plunger and spring means and responsive to the action when said ejector pin is forced inwardly beyond said piercing end, to restrict the motion of said plunger toward said headed portion, whereby when said punch is inverted, the outer extremity of said ejector pin lies substantially ush with the piercing end of said punch; and means responsive to said pin being subsequently forced further into said bore to cause said spring means to force said pin outwardly to a point where said headed portion abuts said shoulder.

4. In a punch, a body portion having a piercing end; a bore and counterbore within said body portion forming a shoulder therebetween; an ejector pin slidingly received Within said bore and having a headed portion slidingly received within said counterbore, said pin extending outwardly beyond said piercing end when said headed portion contacts said shoulder; plunger means mounted within said body portion adapted to contact said headed portion; spring means normally urging said plunger toward said headed portion; and indexing means between said plunger and said spring means, adapted in alternate indexed positions to selectively restrict the motion of said plunger toward said headed portion, whereby when said punch is inverted, the outer extremity of said ejector pin lies substantially ush with the piercing end of said punch.

5. In a punch, a body portion having a piercing end; a bore and counterbore within said body portion forming a shoulder therebetween; an ejector pin slidingly received within said bore and having a headed portion slidingly received within said counterbore, said pin extending outwardly beyond said piercing end when said headed portion contacts said shoulder; plunger means mounted within said body portion adapted to contact said headed portion; spring means normally urging said plunger toward said headed portion; indexing means between said plunger and spring means, adapted in alternate indexed positions to selectively restrict the motion of said plunger toward said headed portion, whereby when said punch is inverted, the outer extremity of said ejector pin lies substantially flush with the piercing end of said punch; and means responsive to the forcing of said pin into said bore behind the piercing end of said punch for actuating said indexing means.

6. In a punch, a body portion having a piercing end; a bore, rst and second counterbores in said body portion forming shoulders between said bore and first counterbore and between said two counterbores; an ejector pin slidingly received within said bore and having a headed portion slidingly received within said tirst counterbore, said pin extending outwardly beyond said piercing end when said .headed portion contacts the shoulder between said bore and rst counterbore; a tubular liner within said second counterbore and including longitudinally extending ribs spaced about the inner periphery of said liner, forming longitudinally extending grooves between adjacent ribs; means for blocking alternate of said grooves; a separate member slidingly received within said liner and having longitudinally extending, spaced ribs about its outer periphery adapted to mate with the grooves between the ribs on said liner; spring means normally urging said separate member toward the shoulder between said two counterbores; rigid means between said headed portion of said ejector pin and said separate member; and means between said rigid means and the ends of said ribs for indexing said separate means each time said pin is forced into said bore beyond said piercing end.

7. In a punch, a body portion .having a piercing end; an ejector pin slidingly received within a bore in said body portion, said pin being restricted in its movement outwardly thereof beyond the piercing end of said punch; spring means normally urging said ejector pin toward its outward restricted position; and separate means wholly within said body portion, coaxial with said ejector pin and permanently located between said ejector pin and said spring means for selectively restricting the outward motion of said pin such that when said punch is inverted, the outer extremity of said ejector pin lies substantially flush with the piercing end of said punch.

8. In a punch, a body portion having a piercing end; an ejector pin slidingly received within a bore in said body portion, said pin being restricted in its movement outwardly thereof beyond the piercing end of said punch; spring means normally urging said ejector pin toward its outward restricted position; and separate means wholly within said body, coaxial with said ejector pin and permanently located between said ejector pin and said spring means, said separate means being adapted, when the outer extremity of said pin is forced inwardly behind said piercing end, to restrict the outward motion of said pin such that when said punch is inverted, the outer extremity of said ejector pin lies substantially flush with the piercing end of said punch.

9. In a punch, a body portion having a piercing end; an ejector pin slidingly received within a bore in said 7,. body portion, said pin being restricted inits movement outwardly thereof beyond the piercing end of said punch; springv means normally urging said ejector pin toward its outward restricted position; and separate means wholly Within said body, coaxial with said ejector pin and permanently located between said ejector pin and'said spring means, said separate means being adapted, when the outer extremity of said pin is forced inwardly behind said. piercing end, to restrict the outward motion of said pin such that when said punch is inverted, the outer extremity of said ejector pin lies substantially flush with the piercing end of said punch, and when said pin is subsequently forced further into said bore, said springmeans forces said pin outwardly to a point where its outer extremity lies outwardly beyond said piercing end.

10 In a punch, a body portion having a piercing end; an ejector pin slidingly received within a bore in said body portion, said pin being restricted in its movement outwardly thereof beyond the piercing end of said punch; spring means normally urging said ejector pin toward its outward restricted position; and indexing means between said pin and said spring means, adapted in alternate.in.

dexed positions to selectively restrict the outward motion of said pin such that when said punch is inverted, the

outer extremity of said ejector pin liesr substantially ush with the piercing end of said punch.

11. In a punch, a body portion having a piercing end; an ejector pin slidingly receivedwithin a bore in said body portion, said pin being restricted in its movement outwardly thereof beyond the piercing end of said punch; spring means normally urging said ejector pin toward its outward restricted position; indexing means between said pinrand said spring means, adapted in alternate indexed positions to selectively restrict the' outward motion of said pin such that when said punch is inverted, the outer extremity of said ejector pin lies substantially flush with the piercingend of said punch; and means responsive to the forcing of said pin into said bore behind the4 piercing end of said punch for actuating said indexing means.

References Cited by the Examiner UNITED STATES PATENTS 2,917,960 12/ 1959 Gargrave 8a3- 128 3,063,319 11/1962 Johnson 83--128 WILLIAM W. DYER, IR., Primary Examiner.

ANDREW R. JUHASZ, Examiner. 

1. IN A PUNCH, A BODY PORTION HAVING A PIERCING END; A BORE AND COUNTERBORE WITHIN SAID BODY PORTION FORMING A SHOULDER THEREBETWEEN; AN EJECTOR PIN SLIDINGLY RECEIVED WITHIN SAID BORE AND HAVING A HEADED PORTION SLIDINGLY RECEIVED WITHIN SAID COUNTERBORE, SAID PIN EXTENDING OUTWARDLY BEYOND SAID PIERCING END WHEN SAID HEADED PORTION CONTACTS SAID SHOULDER; PLUNGER MEANS MOUNTED WITHIN SAID BODY PORTION ADAPTED TO CONTACT SAID HEADED PORTION; SPRING MEANS NORMALLY URGING SAID PLUNGER TOWARD SAID HEADED PORTION; AND MEANS WHOLLY WITHIN SAID BODY, LOCATED BETWEEN SAID PLUNGER AND SPRING MEANS AND RESPONSIVE TO THE FORCING OF SAID EJECTOR PIN INTO SAID BORE SUCH THAT ITS OUTER END IS WITHIN SAID BORE FOR SELECTIVELY RESTRICTING THE MOTION OF SAID PLUNGER TOWARD SAID HEADED PORTION, WHEREBY WHEN SAID PUNCH IS INVERTED, THE OUTER EXTREMITY OF SAID EJECTOR PIN LIES SUBSTANTIALLY FLUSH WITH THE PIERCING END OF SAID PUNCH. 